Surface and transport properties of Au–In liquid alloys

Novaković, R.; Ricci, E.; Gnecco, F.

doi:10.1016/j.susc.2006.08.024

Cited by 15 publications

(12 citation statements)

References 27 publications

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“…Gibbs energy of mixing in the binary Au-In system has been reported by several groups. It was shown that the normalized Gibbs free energy of mixing (GM/RT), under the conditions similar to our NW growth system, has a minimum value of almost −3 at 45.5% In composition, 28 which indicates that the alloying of Au and In lowers the energy of the catalyst significantly. Also, the Au and In alloy is known to show extremely rapid inter-diffusion.…”

Section: Resultssupporting

confidence: 53%

Ultrathin InAs nanowire growth by spontaneous Au nanoparticle spreading on indium-rich surfaces

Jung

Mohseni

2014

Nanoscale

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Ultrathin InAs nanowires (NWs) can enable true one-dimensional electronics. We report a growth phenomenon where a bimodal size distribution (∼ α nm and ∼ 5 nm in diameter) of InAs NWs can be achieved from gold (Au) nanoparticles of a single size, α (α = 50-250 nm). We determine that ultrathin InAs NW growth is seeded by ultra-small Au nanoparticles shed from the large Au seeds upon indium (In) introduction into the growth system and formed prior to the supersaturation of In in Au. The Au spreading phenomenon is explained by the balancing of Gibbs free energy lowering from In-Au mixing and the surface tension increase. Ultrathin InAs NWs formed in this way exhibit a perfect wurtzite structure with no stacking faults. We have observed InAs NWs with diameters down to ∼ 2 nm using our growth method. Passivating the ultrathin InAs NWs with an AlAs shell, subsequently oxidized in air, results in physical deformation of the InAs core, demonstrating the mechanical pliability of these ultrathin NWs.

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Section: Resultssupporting

confidence: 53%

Ultrathin InAs nanowire growth by spontaneous Au nanoparticle spreading on indium-rich surfaces

Jung

Mohseni

2014

Nanoscale

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“…Most of the variables used were found in literature − and are explained in more detail in the Supporting Information. The solid–liquid energy of the nucleus was initially varied as a fitting parameter.…”

mentioning

confidence: 99%

Simulation of GaAs Nanowire Growth and Crystal Structure

et al. 2019

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Growing GaAs nanowires with well-defined crystal structures is a challenging task, but may be required for the fabrication of future devices. In terms of crystal phase selection, the connection between theory and experiment is limited, leaving experimentalists with a trial and error approach to achieve the desired crystal structures. In this work, we present a modeling approach designed to provide the missing connection, combining classical nucleation theory, stochastic simulation, and mass transport through the seed particle. The main input parameters for the model are the flows of the growth species and the temperature of the process, giving the simulations the same flexibility as experimental growth. The output of the model can also be directly compared to experimental observables, such as crystal structure of each bilayer throughout the length of the nanowire and the composition of the seed particle. The model thus enables for observed experimental trends to be directly explored theoretically. Here, we use the model to simulate nanowire growth with varying As flows, and our results match experimental trends with a good agreement. By analyzing the data from our simulation, we find theoretical explanations for these experimental results, providing new insights into how the crystal structure is affected by the experimental parameters available for growth.

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“…Surface Energy Estimation . On the basis of the composition, we estimated the surface tension based on linear combination of the surface energy of Au and Ga . By sorting the collected data depending on the interface morphology (truncated or flat corner), we fitted the solid–vapor surface energy, based on the surface tension, to agree with our observations.…”

Section: Methodsmentioning

confidence: 68%

“…Assuming that the imaging of the droplet is a two-dimensional projection of a spheroidal cap, and that any change in droplet volume relates to Ga concentration, this allows for an estimation of the droplet composition for each frame of interest. From the composition, the surface tension is estimated by linear extrapolation from the pure species (Au and Ga), and details on the estimation are provided as Supporting Information. Each extracted data point is then related to whether a truncation has occurred recently (within 0.5 s), presented as green or black in Figure .…”

mentioning

confidence: 99%

Limits of III–V Nanowire Growth Based on Droplet Dynamics

Tornberg

Maliakkal

Jacobsson

et al. 2020

J. Phys. Chem. Lett.

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Crystal growth of III-V semiconductor nanowires assisted by a liquid particle/droplet occurs at the solid-liquid interface. This makes the stability of a droplet on the top of a nanowire crucial for successful nanowire growth. Using in-situ transmission electron microscopy together with theoretical analysis of the capillary forces involved, we conclude that truncation of the solid-liquid interface extend the stability range for a droplet in contact with the nanowire top interface. This provides insights to the limits of nanowire growth and is used to experimentally estimate the surface energy of the wurtzite {1 1 2 0} facet of GaAs.Epitaxial crystal growth of semiconductor nanowires assisted by a liquid-particle relies, in a simple perspective, on two fundamental principles: nucleation of material, and a liquid covering the growth front. As in many cases of crystal growth from a melt, the wetting angle, or the contact angle between the growing crystal and the melt, is of importance for crystal formation [1,2]. For nanowires grown by the vapor-liquid-solid (VLS) mechanism, a fundamental stability criterion for having a droplet at the nanowire top has been proposed by Nebol'sin and Shchetinin[3] based on ex-situ observations and earlier theoretical work [4][5][6].Since their report on this stability limit, several experimental[7-11] and theoretical [12][13][14][15] investigations of nanowire growth focusing on the wetting properties of the liquid metal catalyst have been reported, often with focus on its influence on nucleation [8,9] rather than the droplet wetting dynamics. Still, this Nebol'sin-Shchetinin stability criterion remains generally accepted, perhaps due to the simplicity of the model. The Nebol'sin-Shchetinin model predicts an upper bound for having a droplet on the top nanowire facet by relating the ratio of the surface energies of the solid and liquid phases in contact with the vapor (γ sv and γ lv ) to the wetting angle and tapering of the nanowire[3].Although the model is widely accepted, it has important limitations: for instance growth of self-assisted GaAs [16] and InAs [17] have been extensively reported, although the relevant surface energy ratios are in these cases greater than the predicted upper bound (γ sv /γ lv ∼ 2 compared to √ 2 for un-tapered nanowires[3]). A limitation of the existing model is the assumption that the interface between droplet and nanowire is flat, which, according to experimental results [8,9,18], is not always the case during growth. These experimental reports have shown the formation of a truncation of the top nanowire facet during growth,

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Surface and transport properties of Au–In liquid alloys

Cited by 15 publications

References 27 publications

Ultrathin InAs nanowire growth by spontaneous Au nanoparticle spreading on indium-rich surfaces

Ultrathin InAs nanowire growth by spontaneous Au nanoparticle spreading on indium-rich surfaces

Simulation of GaAs Nanowire Growth and Crystal Structure

Limits of III–V Nanowire Growth Based on Droplet Dynamics

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